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Expanding upon previous research, a University of Missouri veterinary neurologist has found that a biomarker test used to diagnose ALS in humans can also be applied to canines who exhibit symptoms of degenerative myelopathy (DM).

DM is a progressive disease of the spinal cord, which afflicts older dogs. Typical onset of symptoms begins in canines from 8- to 14-years-old. It has been confirmed in more than 30 pure bred breeds, including German Shepherds, boxers and Pembroke Welsh corgis, as well as some mixed breed dogs.

Currently there is no definitive diagnostic test or effective treatment for canine DM. Instead, veterinarians have to play a game of elimination, and rule out the possibility of other conditions before determining if a dog does have DM. Even then, the disease can only be confirmed from an autopsy.

Similar to ALS, early symptoms of DM include a loss of coordination in the hind limbs, which continues to progress until full paralysis sets in. It is caused by degeneration of white matter in the spinal cord.

In 2009, Joan Coates, veterinary neurologist at the University of Missouri, and fellow researchers identified a genetic link between DM in dogs and ALS in humans. Following up on this finding, Coates has now found that a biomarker test that helps diagnose ALS can also assist in providing a conclusive diagnosis of DM.

Genetic testing can be done to predict the risk of a specific dog developing the disease, which proves useful for both breeders and veterinarians, but an effective diagnostic test is still needed.

ALS is tested through phosphorylated neurofilament heavy proteins (pNF-H) that are released into spinal fluid and blood. These biomarkers are released during the degeneration of spinal tissues, offering a good indication that ALS is present.

Coates set out to determine if this concept would work in canines. Results were published in the Journal of Veterinary Internal Medicine.

The study included 53 DM-affected dogs, 27 neurologically normal ones, seven asymptomatic but at-risk dogs and 12 DM mimic dogs.

Cerebrospinal fluid and blood samples were collected from the dogs in numerous stages of the diseases. pNF-H concentrations from those samples were compared to samples from age-matched healthy dogs and dogs with mimicking diseases.

“We found a significant difference in the DM-affected dogs,” Coates said. “pNF-H levels were increased in the cerebrospinal fluid of the DM-affected dogs relative to the control groups, indicating that the human ALS test could be used to diagnose DM. These results will enable us to ‘scale up’ the test to make it more accessible to veterinary community.”

Additionally, Coates is seeking clinical trial participants to evaluate treatments for canine DM. She hopes the therapies being tested slow the progression of neurologic signs of DM and improve quality of life for canines. The clinical trials are taking place at the MU Veterinary Health Center (VHC) Small Animal Hospital.

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